Light source diode

Besides their applications as tunable light sources, diode lasers are more and more used as pump lasers for tunable solid-state lasers and optical parametric amplifiers. Monolithic diode laser arrays can now deliver up to lOOWcw pump powers [5.124]. 

Fig. 4. Lrft) Schematic of the MCS 2 x 512 VIS color-measuring instrument, consisting of two identical spectrometer modules and the movable measuring head with integrating sphere and flash tube. Right) Measuring setup for the thickness measurement of films and layers, consisting of light source, diode array spectrometer, and fiber bundles (38).

The light source for excitation of Nd YAG lasers may be a pulsed flashlamp for pulsed operation, a continuous-arc lamp for continuous operation, or a semiconductor laser diode, for either pulsed or continuous operation. The use of semiconductor laser diodes as the pump source for sohd-state lasers became common in the early 1990s. A variety of commercial diode-pumped lasers are available. One possible configuration is shown in Figure 8. The output of the diode is adjusted by composition and temperature to be near 810 nm, ie, near the peak of the neodymium absorption. The diode lasers are themselves relatively efficient and the output is absorbed better by the Nd YAG than the light from flashlamps or arc lamps. Thus diode-pumped sohd-state lasers have much higher efficiency than conventionally pumped devices. Correspondingly, there is less heat to remove. Thus diode-pumped sohd-state lasers represent a laser class that is much more compact and efficient than eadier devices. 

For the visible and near-ultraviolet portions of the spectmm, tunable dye lasers have commonly been used as the light source, although they are being replaced in many appHcation by tunable soHd-state lasers, eg, titanium-doped sapphire. Optical parametric oscillators are also developing as useful spectroscopic sources. In the infrared, tunable laser semiconductor diodes have been employed. The tunable diode lasers which contain lead salts have been employed for remote monitoring of poUutant species. Needs for infrared spectroscopy provide an impetus for continued development of tunable infrared lasers (see Infrared technology and RAMAN spectroscopy). 

They may be classified by their structure, as coin, cylindrical and pin types. Table 5, 6, 7 respectively show their specifications. Applications of Li -(CF)n batteries as power sources are spreading from professional and business uses, such as in wireless transmitters and integrated circuit (IC) memory preservation, to consumer uses in electronic watches, cameras, calculators, and the like. Pin-type batteries are used for illumination-type fishing floats with a light-emitting diode. Coin-type batteries, which have a stable packing insulation, separator, and electrolyte for high... 

Single Mode. The single-mode fiber has a step-index profile (Fig. 16.6c) and a small core diameter (typically 10 im) such that only one mode can travel through it. This is now the preferred system, particularly for long-distance transmission. The normal light source for multimode fibers is the light-emitting diode (LED). But... 

Moser, C., Mayr, T. and Klimant, I. (2006). Filter cubes with built-in ultrabright light-emitting diodes as exchangeable excitation light sources in fluorescence microscopy. J. Microsc. 222, 135—40. 

Figure 12. Schematic lay-out of compact optical sensor chip without need of external optical apparatus with identical microresonators as sensors LED broad band source, for example Light Emitting Diode, MR-F microresonator used as optical filter, MR-S microresonator used as optical sensor, PD Photo Diode.

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